Automated saw

ABSTRACT

The automated saw has a saw table and saw superposed over the table for movement there across at selected angles. Board-lengthpositioning devices are spaced along the saw table. The variable angle saw and the variable-length-positioning devices are controlled by an input including predetermined numerical information. The saw is set up that single and double cuts can be made at opposite ends of the boards with the board length and saw angle positioning devices being automatically preset by the numerical information input.

United States Patent Jureit et al.

AUTOMATED SAW Inventors: John C. Jureit, Coral Gables, Fla;

Lawrence A. Hoffman, Potomac, Md.

Assignee: Automated Building Components,

I Inc., Miami, Fla.

Notice:

The portion of the term of this patent subsequent to Oct. 5, 1988, hasbeen disclaimed.

Filed: Nov. 28, 1973 Appl. No.: 419,819

Related US. Application Data Continuation of Ser. No. 113,012, Feb. 5,1971, which is a division of Ser. No. 549,624, May 17, 1966, Pat. No.3,610,299.

US. Cl. 83/71; 83/268; 83/364; 83/471.3; 83/485 Int. Cl B27b 5/20; B26d5/30 Field of Search 83/71, 268, 360, 364, 361, 83/467, 468, 471.3,471.2, 485

mul mull!" 3 Al F coma,

[56] References Cited UNITED STATES PATENTS 3,141,367 7/1964 Keener83/268 X 3,176,556 4/1965 Roberts et al. 83/71 3,329,181 7/1967 Buss etal 83/364 3,610,299 10/1971 Jureit et a] 83/71 Primary ExaminerDonald R.Schran Attorney, Agent, or Firm-LeBllanc & Shur [5 7 ABSTRACT Theautomated saw has a saw table and saw superposed over the table formovement there across at selected angles. Board-length-positioningdevices are spaced along the saw table. The variable angle saw and thevariable-length-positioning devices are controlled by an input includingpredetermined numerical information. The saw is set up that single anddouble cuts can be made at opposite ends of the boards with the boardlength and saw angle positioning devices being automatically preset bythe numerical information input.

13 Claims, 19 Drawing Figures US, mm 0%. 7,1975 Sheet 1 of 8 3,910,142

wwawl M Q UUUUU b mv N mum NNM Lawrence A. Hoffman '5 J A L V ATTORNEYUS. amm 0a. 7,1975 Sheet 2 of8 3,910,142

/ UNDERSIZE NORMAL 2 x 2 [D OVERSIZE Hash a I l I l I 232} UNDERSIZENORMAL 2x8 OVERSIZE 25m REST posmou most 1 cuwws US. Patent 00. 7,1975Sheet 3 of8 SET T0 0 INV Z40 STEP RING COUNTER US. PDLYIIDITI. 00L7,1975 Sheet 4 of 8 3,910,142

392 TO CLAMPS,

MANUAL COMMANDS $AWS,ETC- 320 322 336 \FROM MACHINE sENsoRs W394MATERIAL OPERATION BOARD WIDTH INDEXING AND INsTRucTION INSTRUCTIONsELEcTION CUTTING OPERATION DISPLAY PANEL DISPLAY PANEL GENERATORPROGRAMMER TAPE INSTRUCTION OPERATION READER TRANsLATOR SEQUENCER 32 378362 368 INDfiER TAPE STEPPING 380 r LOGIC 342\\ DIMENSION a 345 385 UNITANGLE LENGTH I MEMORY L- INDEXER 384 376 (ICOAYRSE) 330 P564 348 386 EMANUAL ANGLES: LgN H w DIMENsION sET F/G /0 SWITCHES (FINE) 390 664REvERsE FORWARD 538 sTEP FROM A: I 672 I I 677 TRANsLAToR 5 DIRECTION692 OR REGISTER 9 I AND ZERO sTEP 3 I L sENsOR MOTOR m l 3 I f 674 CLEAR676 REEER-ENOE D POSITION PRESENT sENsOR POsITION I 6'84\ A I. 55REGISTER sTART 680 INDEXER SET TO REFERENCE INDExER BALANCED US. Patent0a. 7,1975 Sheet 7 of8 3,910,142

US. Patent Oct. 7,1975 Sheet 8 of8 3,910,142

AUTOMATED SAW This application is a continuation of Application Ser. No.113,012 filed Feb. 5, 1971 and which Application Ser. No. 113,012 is adivision of Application Ser. No. 549,624 filed May 17, 1966, now U.S.Pat. No. 3,610,299 dated Oct. 9, 1971.

This invention relates to an apparatus for manufacturing structuralwooden devices, and more particu larly to apparatus for cutting chordsor segments of structural wooden devices such as roof trusses and thelike.

With the advent of the connector plate shown in Jureit, US. Pat. No.2,877,520, it became possible to manufacture structural wooden devicessuch as roof trusses without the necessity of manual nailing, bolting orgluing. These connectors comprise steel plates having slender, elongatednaillike teeth struck therefrom in three or more rows so as to extendsubstantially perpendicular to the plate. Structural wooden butt jointsemploying such connectors may be formed by simply sandwiching the twobutted wooden members between pairs of the Jureit plates andsimultaneously pressing the teeth of both plates into the lumber to forma completed joint. The operation is rapid, low in cost, and provides abuilt-in quality, in that there is no necessity to rely upon the propernumber of nails, bolts or other fasteners being manually affixed in theformation of the joints. The widespread adoption of such joints hasresulted in concurrent improvements in other aspects of the trussfabrication procedure.

For example, because all roof trusses of a particular configuration arecomprised of component parts of the same shape, it has proved convenientto prepare the components for assembly in a systemstized or productionline manner, even further reducing the fabrication time and costthereof. If a particular truss is comprised of four distinctly shapedchords or boards and 100 trusses are to be produced, 100 boards of thefirst shape are cut, then 100 boards of the second shape, etc. All ofthe precut components are then appropriately arranged, and assembled bymeans of so called truss presses such as shown in Jureit US. Pat. No.3,195,449. Typically, the cutting process is carried out by means ofconventional type table saws, adjustable radial arm saws, etc. Thisprocess has proven to be quite successful.

Further, it has been found advantageous to systematize to a largedegree, other phases of the design and manufacturing process, both inthe interest of quality and economy. In particular, computing equipmenthas been utilized to actually design trusses upon specification of theoverall configurations thereof, starting materials, etc. Thus, uponspecification by the architect of the general shape, etc., of thedesired truss, the computer can very rapidly calculate the appropriatelengths and angles of the component boards, and produce seale drawingsthereof, appropriately labeled as to dimensions, type of stock material,etc. These drawings are directly provided to the sawyers and assemblerswithout the cost and delay of manual design.

As the use of roof trusses employing Juriet-type connector plates becamemore widespread, the demand grew for the production of widely varyingtypes of trusses which would permit architects increased freedom of roofdesign. Use of such trusses permits the erection of low-cost homes withvarying roof lines, so as to avoid the growth of communities wherein allhouses are identical. Due to the wide variety fo possible truss designsand board shapes, there results a situation in which a substantiallyunlimited number of board length and cutting angles may be specified bythe architect. As a result, the various cutting and fabricationtechniques referred to above, lose their systematized or production linenature since each segment of the truss may well be of a differentlength, etc., and few successive trusses will require the same segments.Such board-to-board uniqueness greatly increases the amount of timenecessary to assemble a given roof truss since it is generally notpossible to mass produce the segments before assembly.

According to the present invention, it has been found to be possible toautomate the work of the sawyer to such a great degree, as tosubstantially overcome the problems of uniqueness of the segments ofspecial trusses. Briefly, according to one embodiment of the invention,there is provided a fabrication machine including a single numericallycontrolled variable angle saw and a numerically controlled variablepositioning device, whereby the proper angle and length of board can beautomatically established during the time that the sawyer is placing theboard on the machine. The de vice may be controlled by punched ormagnetic tape or by punched cards carrying information generated by theabove-described computing machines in response to the specification ofthe gross'characteristics of the truss. The information necessary tofabricate all of the segments of a single truss may be provided seriallyon the tape or on a deck of cards whereby the operator need only insertthe same into a tape or card reader and is automatically provided withall of the information necessary to rapidly fabricate the truss.

Such information includes all of the dimensions of the starting materialto be used, as well as indications of when to insert, remove, or advanceeach board in order to cut truss members having one or two angles ateach end. All of the indications are appropriately displayed for use bythe operator. Since a single saw is used in the above-describedembodiment, after one end of the board is cut, it is advanced andreinserted in the machine. During the time that the board is beingadvanced, the appropriate saw settings are automatically recorded,whereby upon reinsertion of the board, the second cut may beautomatically made.

In addition, to provide great flexibility the machine can cut boardshaving one ortwo cuts at each end with no adjustment or modificationbetween cuts.

As may be understood, considerable variation may be expected in thelengths of both the starting material and the completed segments. Forexample, the re quired stock length may vary from 2 to 24 or more feet.Accordingly, it is a feature of the invention that there is provided atwo-step, numerically controlled positioning arrangement in which thecutting position is set concurrently by coarse and fine adjustments.

It is also a feature of the invention that means are provided to adjustthe angular position of the saw blade whereby such blade always crossesthe cutting surface in approximately the same place irrespective of theangle setting, and where the lumber is moved in one direction only tomake each subsequent cut. This simplifies the construction of themachine as well as the design of the components of the truss.

A further feature of the present invention relates to designdifficulties that exist due to variation of the dimensions of the stockmaterial, A 2X4 for example i may vary somewhat about its nominal widthof 3% inches, perhaps as much as 1/16 inch. As a result, if the lengthand angles of the segments are specified for boards of nominaldimensions and the particular boards used are either over or under thenominal size, it will be found that the truss will not fit togetherproperly.

Thus, the possibility of such size variations must be taken into accountin the design of the truss components, and accordingly it has been foundto be desirable to specify three dimensions and three angles for eachsegment, the appropriate ones of which to be selected by the sawyerafter measurement of the width of the stock material to be used.

According to this invention, means are provided for automaticallyselecting the appropriate set of dimensions and angles to be used inaccordance with the board width. In fact, it has been found that it ispossible to entirely automate the selection process even to the extentof automatically measuring the width of the boards.

As may be understood, use of the concepts of the present inventiongreatly facilitates the fabrication of special roof trusses, since theextreme accuracy of angle and length settings needed for proper fit isaccomplished rapidly and automatically without the expenditure ofoperator time. In addition, if desired, the fabrication line is readilyadaptable to the manual setting of the dimensions and angles whereby theequipment may-be utilized in the mass production techniques foruniformly shaped trusses described above.

In an alternative embodiment of the invention, there may be provided avariable length fabrication line having one fixed and one longitudinallymovable saw, the separation and angular settings of which saws aredetermined by numerical information provided on punched cards or tape.Again, all of the information necessary may be provided on the tape andregistered on a display panel in view of the sawyer. A two-sawembodiment has the advantage that less time is required to cut eachboard.

Accordingly, it is a primary object of this invention to provideimproved apparatus for fabricating wooden members of variable specifiedshapes and dimensions.

It is also an object of this invention, to provide a fabrication machinepermitting the rapid and low cost manufacture of component members forwooden roof trusses of variable special shape.

It is also an object of this invention, to provide an improvedfabrication line whereby each of the segments of a roof truss may berapidly and accurately cut to specified sizes and shapes.

It is an additional object of this invention to provide an automatedfabrication machine including one or more angularly adjustable saws andhaving provision for accurately establishing the final length of the cutboard.

It is a further object of this invention to provide a fabricationmachine as described above which automatically compensates forvariations above and below the nominal width of the stock material to befabricated.

It is a further object of this invention to provide a saw machine asdescribed above including a single s aw and a variably positionablemeasuring means for adjusting the cutting length.

It is also an object of this invention to provide a fabrication machineas described above including means to adjust the length to which theboard is cut having separate coarse and fine adjustments.

It is an additional object of this invention to provide a fabricationmachine as described above where each saw blade crosses the cutting areaat the same point, in dependent of its angular adjustment.

It is also an object of this invention to provide a machine as describedabove in which the lumber to be cut moves only in one directionthroughout the cutting process.

The exact nature of this invention, as well as other objects andadvantages thereof will become clear from the following specification,and the annexed drawings, in which:

FIG. 1 is an overall perspective view showing the details of oneembodiment according to the present invention;

FIG. 2 is a sectional view taken along line 2--2 in FIG. 1 showing themanner of construction of a portion thereof;

FIG. 3 is a side elevation, partially in section, and partially cutaway, showing the construction of the saw according to the presentinvention;

FIG. 4 is a front elevation, also partially in section, and partiallycut away, of the mechanisms shown in FIGS. 1 and 3;

FIG. 5 is a partially cut away plan view of the apparatus shown in FIGS.1, 3 and 4 showing the manner in which the saw blade angle and thelength of the segment to be out are adjusted;

FIG. 6 is a perspective view of one of the variable lumber stops used toestablish the length of the segment to be cut;

FIG. 7 is a schematic view of one of the combined lumber clamp and boardwidth sensors used to identify an oversized, normal or undersize pieceof lumber;

FIG. 8 is an end view of a portion of FIG. 7 showing the details of theconstruction thereof;

FIG. 9 is a schematic view of a further portion of FIG. 7 showing themanner in which an oversize, normal, or undersize piece of lumber isidentified;

FIG. 10 is a generalized overall block diagram of the numerical controlsystem used in the present invention;

FIGS. 11a through show illustrative configurations which may be assumedby a truss segment and which may be conveniently accommodated by theapparatus of the present invention.

FIGS. 12 through 17 are detailed block diagrams showing various portionsof the numerical control system generally shown in FIG. 10.

Referring first to FIG. 1, there is shown an overall perspective view ofa single saw embodiment of the fabrication machine according to thisinvention. The apparatus generally denoted at 10 comprises a central sawtable 12, a conveyor table 14, and a measuring table 16 arrangedlongitudinally to provide an extended working surface upon which thelumber is cut. The apparatus also includes an electronic console 18positioned within convenient reach and view of the operator.

Saw table 12 comprises a pair of vertical side members 2 and 22 and atop member 24. Below top member 24 is positioned a horizontal shelf 26having a front facing 27 which provides a support for pivotally mountinga radial arm saw 28 in a manner explained below. Also disposed below topmember 24 within convenient reach of the operator is a suitabledust-proof receptacle having a plurality of push buttom electricalswitches 34 projecting therefrom. In the present embodiment, 4 suchswitches are provided, and serve the functions of initiating the variousmanually-controlled operations included within the sequence of steps bywhich a truss is cut.

Conveyor table 14, a portion of which is shown, is rigidly attached toside member 22 by a pair of horizontal rails such as 36 extendingoutwardly at the bottom of saw table 10. Conveyor 14 incljdes a numberof legs 38 and extended members 40 and 42 forming the bottom thereof.Mounted upon'legs 38 are a pair'of horizontal rails 44 and 46 having aseries of aligned aperatures 48 for rotably receiving a plurality ofrollers 50 on which the lumber may be conveniently transported. Table 14may also include a number of diagonal bracing members such as 52 betweenrails 44 or 46 and nearby legs 33. As may be understood, conveyorportion 14 is made of sufficient length to support the maximum sizelumber to be cut.

Measuring table 16 is positioned at the opposite end of saw table 10 andmay be rigidly bolted thereto by means of a pair of brackets 54. Table16 serves the dual purpose of supporting the lumber while it is beingcut, as well as accurately and rapidly establishing the distancesbetween cuts. Table 16 is comprised of a supporting frame 56 and ahorizontal stop carriage 58 slidably mounted thereon as described below.Frame 56 comprises of a pair of identical front and rear frames 60, eachhaving a pair of legs 62 and 64 and a crosspiece 66 therebetween.Connected between legs 62 and 64 at the upper ends of both front andrear frames are a pair of right angle beams 68 and 70, respectively,having horizontal surfaces 71 and vertical surfaces 72. Front and rearframes 60 are rigidly connected by a horizontal H-frame 73 including alongitudinal member 74 and a pair of transverse members 76 and 78.

Each of beams 68 and carries a plurality of upright rollers 80 tosupport and guide stop carriage 58. Each roller 80 comprises acylindrical retainer disc 82 spaced above horizontal surface 71 of theright angle beam 70 by a cylindrical roller 84 (see FIG. 2). Disc 82 andcollar 84 are rotatably mounted on a pin 86 which extends through anaperture 88 in beam 70. Pin 86 includes a head portion 90 and an uppershank portion 92, having a greater diameter than aperture 88, wherebythe pin rests on surface 71. The length of upper shank 92 is somewhatgreater than that of collar 84, so that both disc 82 and collar 84 arefreetto rotate. Pin 86 also includes a threaded lower shank portion 94by which it may be bolted to beam 70.

As seen in FIG. 2, stop carriage 58 includes a stepped edge 96 and ashoulder 98 adapted to rest on surface 71 of beam 70. Shoulder 98 is ofthe same height as sleeve 84 and the transverse distance between therows of rollers 80 is sufficient to assure freedom of motion forcarriage 58 as it travels along table 16.

Mounted along the rear edge of carriage 58 are a plurality of supportingbrackets 99, each of which supports a pneumatic cylinder 100 positionedat one-foot intervals along the carriage. Each of cylinders 100 isfitted with a piston 102 which extends and retracts a shaft 104.Attached at the end of each shaft 104 is a plate 106 the side 107 ofwhich serves as a stop against which the piece of lumber to be cut maybe positioned. Pistons 102 are operated by compressed air delivered overan airline 108 from a suitable compressor 110 mounted under table 16, orbelow shelf 26 on saw table 12. Each of lines 108 is connected by asolenoid operated valve (not shown) to the common pressure source 110.The pressure drives piston 102 against a compressable coil spring 112mounted on shaft 104 within cylinder 100. When the associated solenoidis released, the pressure against piston 102 is relieved, whereby spring112 returns piston 102 to its rest position and retracts stop 106. Thelength of shaft 104 and stop 106 are preferably designed so that whenpiston 102 is in its rest position the front edge 114 of stop 106provides a convenient support and guide against which the lumber to becut may rest.

As explained below, carriage 58 will generally be adjusted while lumberis resting thereon. Accordingly, means are provided in the form of oneor more rollers 116, similar to rollers 50 mounted in transverse slots118 in carriage 58. Rollers 1116 are freely mounted in any convenientmanner as by a pair of axial pins such as 120 adapted to be received ina pair of aligned reces ses such as 122 shown in FIG. 2.

With particular reference to FIGS. 4, 5 and 6 stop carriage 58 is seento include an elongated tongue portion 124 which is adapted to fit intoa complementary slot 126 in the side of saw table top member 24. Theextreme end 128 of tongue 124, i.e. the left hand end includes a furtherslot 130 within which is positioned a lumber stop which serves the samepurpose as previously described stops 106 shown in FIGS. 1 and 2.

In order to facilitate construction and use, stop 132 is mounted at theend 128 of tongue 124 with the front surface 133 adapted to engage thelumber and is arranged to pivot outwardly from the slot under theinfluence of a lever 134, angularly depending from the undersidethereof. Lever 134 includes a forked end 136 within which is pivotallymounted an elongated shaft 138. A pneumatic cylinder 140 is mounted onthe underside of tongue end 128, and is adapted to receive the other endof shaft 133, and to reciprocate the shaft by means of a piston (notshown) in the manner described in connection with shaft 104 (see FIG.2). As may be understood, a spring, similar to spring 112 in FIG. 2 ispositioned with cylinder 140 between the piston and the rear wall 142 ofthe cylinder, and the compressed air is supplied at the left end 144thereof, so that in its rest position, shaft 138 is extended and lumberstop 132 is retracted, surface 133 being flush with the top of tongue124.

As previously mentioned, each of stops 107 is precisely located at onefoot intervals along stop carriage 58. In like fashion, stop 132 is alsolocated a distance d, 1 foot from the nearest one of stops 106. Thus,assuming carriage 58 to be fixed, selective operation of one of stops106 or stop 132 will provide reference lengths at one foot intervals atwhich lumber may be cut. However, to provide for accurate guides atintervals between each one-foot stop, carriage 58 is adapted to movelongitudinally between rollers 80 under the control of a lead screw 146and a threaded follower 148 (see FIGS. 4 and 5). As shown, screw 146 isconnected to a motor 150, which is preferably a step motor ofconventional design and is secured to the underside of table top 24 by abracket 152. Similarly, follower 148 depends downwardly from the undersurface of carriage 58, in accurate alignment with screw 146.

As described below, step motor 150 is automatically operated to adjustthe position of the stop carriage 58 with an accuracy of 1/32 inch overa one foot interval. Thus, there is provided an accurate cutting guideby first lifting a stop 106 or 132 to afford a coarse adjustment and themoving the entire stop carriage to provide the fine adjustment.

Referring still to FIGS. 1 and 3-5, there is shown the construction ofsaw table 12 and the automatic radial arm saw 28. Resting on tablesurface 24 is a supporting plate which may be comprised of a pair ofspaced apart sections 162 and 164 having a wooden plank 166 insertedtherebetween which serves a protective cutting surface for the saw blade168.

Plate sections 162 and 164 carry a number of pneumatically operatedclamps such as that denoted at 154, and a single combination clamp andboard-width sensor 156 (on plate section 162) which serve to rigidlysupport the lumber 157 to cut against an elongated wooden member 158which serves as a guide fence. Guide fence 158 is rigidly supportedagainst the front sides 159 of a pair of upright brackets 160, bolted orotherwise secured to both table top 24 and supporting plate 152. On eachof brackets 160 is mounted a vertical hold-down clamp such as 161 tofurther support the lumber 157 while it is being cut.

The construction of horizontal clamps 154, combined clamp andboard-width sensor 156 and vertical hold-down clamps 161 is shown inFIG. 7. The clamp comprises a pneumatic cylinder 169 having therein acompressible spring 170 and a piston 172. The rear portion 194 ofcylinder 169 includes a first port 176 connected through a solenoidoperated valve 178 to a source of compressed air, such as compressor 110shown in FIG. 1. The rear portion 194 of the cylinder also includes asecond port 180 by which the cylinder may be externally vented through asecond solenoid operated valve 182. The solenoid for valve 178 isadapted to open the valve in response to the actuation thereof while thesolenoid for valve 182 closes the valve upon actuation. Thus, a singlesignal operates both solenoids, and the presence or absence of thesignal automatically initiates the operation of piston 172. A pair ofshafts 184 and 186 are disposed on opposite sides of piston 172 and areadapted to be driven thereby.

When the signal is present, air is introduced into cylinder 169 andpiston 172 is forced against spring 170. The spring is compressed, andshaft 184 advances through an aperture 188 in front wall 190 of cylinder169, while shaft 186 recedes through a similar opening 192 in rearcylinder wall 194. When the electrical signal is removed, the cylinderis vented and spring 170 forces piston 172 to return to its restposition. Mounted at the forward end of shaft 184 is a clamping block196 which is adapted to bear against the lumber 174 to keep it rigidlyin place against guide fence 158. Clamping block 196 is constructed soas to furnish an electrical indication when it reaches the maximumextension permitted by the particular piece of lumber 157 so thatfurther operations of the machine are provided until the lumber is fullylocked in place against fence 158.

To this end, the front face 198 of block 196 includes a cavity 200 inwhich is pivotally mounted a hinged plate 202 which serves as a sensor.Plate 202 is biased outwardly from block face 198 by a compressablespring 204 which is chosen to apply a substantial outward force againstthe plate. The force is overcome only when the clamp has extended asufficient distance to fully lock the lumber 147 in place between block196 and fence 158 as shown in outline in FIG. 7.

When plate 202 is forced into cavity 200, a microswitch 206 mountedtherein adjacent the pivot point 208 of plate 202 is closed bymechanical contact of plate 202 against microswitch actuator 210. Uponclosure of switch 206, an electrical signal is provided over a coiledconductor 212 (which has sufficient extended length to convenientlyaccommodate the maximum required travel of shaft 184) to a coincidencegate 214. Similar signals are provided from all of the other clampswhereby, until all are fully closed, no output is present from gate 214.The gate output may be used as an electrical inerlocking signal by theremainder of the system as described below in order to conditionsubsequent steps in the cutting program only after all of the clamps arecompletely closed.

As shown in FIGS. 7 and 8, secured to the end of rearwardly extendingsahft 186 is a collar 216 having thereon an upwardly bent flange 218.Shaft 186 and collar 216 are positioned Within a dust-proof enclosure220 which houses a lamp 222, a first photodetector 223, and a furtherplurality of photocells 224. Shaft 210 is separated from lamp 222 by anextended plate 226 having a plurality of small apertures 228, eachaligned with one of photocells 224. A further aperture 229 is alignedwith photodetector 223. Each of apertures 228 and 229 are made quitesmall, in order to minimize the amount of stray light which might passthrough a given aperture to one of the nonaligned photocells.

Photocells 223 and 2324 are enclosed in a small light-proof housing 230attached to the outer wall 232 of dust proof enclosure 220, whichcomprises a plate having apertures aligned with photocells and 229 tofurther minimize the effects of stray light.

As may be understood, the force of the compressed air on piston 172 willcause the movement of shaft 186 so that flange 218 successively blocksand unblocks one or more of photocells 224, the number of such cellsblocked being determined by the thickness of the piece of lumber 147. Asthe light to successive cells 224 is blocked, signals are generated andpass along leads 236 to a gating circuit 238, which is adapted toprovide a signal at output 240 each time a photocell is blocked. Output240 is connected to the stepping input of a 13 position ring counter342, having states denoted as M through M whereby each time a photocellis blocked, ring counter 242 is advanced to the next state.

Photocell 223 and aperture 229 are so positioned that when piston 172 isin its rest position, flange 218 will prevent light from reaching it.The output of photocell-223 is connected through lead 244 and aninverter circuit 246 to a further input 248 of ring counter 242 andserves to reset and hold the counter in its M state whenever clampingblock 196 is fully retracted and cell 223 is blocked. Whenever air isintroduced into cylinder 169 and the clamp moves forward, successivemovements will cause ring counter 242 to be advanced through its states,thereby giving a quantized indication:

of the width of the piece of lumber being cut.

In FIG. 9 is shown schematically the apertures in plate 232 wherebynormal, oversize, and undersize indications may be provided for each ofthe board widths 1 to be cut. As may be seen, a first aperture 250labelled rest position is aligned with photocell 223 to reset ringcounter 242. Following aperture 250 is a group of three apertures 252,254, and 256, which is so located that when a large board, e.g. a 2X8 isbeing cut, a slightly oversized board will cause clamping block 196 totravel only a sufficient distance so that the photocell in aperture 252alone is blocked. If the 2X8 is of normal dimensions, the clamping blockwill travel a sufficient distance to cause first aperture 252 andaperture 254 to be covered, causing ring counter 242 to step first intoits M state (upon the blocking of aperture 252) and then into its Mstate (upon the blocking of aperture 254). Similarly, if the 2X8 boardis somewhat undersized, then in addition to the above, the travel ofclamping block 196 will cause aperture 256 also to be blocked, advancingcounter 242 to its M state. As may be understood, the areas 258 and 260shown in FIG. 8 contain no photo cells, therefore, a quantizedindication of the board width will be given. Such quantized indicationof the board width is satisfactory for all practical purposes.

Referring still to FIG. 9, at the other end of wall 232, are positioned3 apertures 262, 264, and 266, which provide an oversize, normal, andundersize indication respectively when clamping board 196 travels itsmaximum distance, i.e. for the narrowest board, in this case a 2X2. Inother words, the first, fourth, seventh and tenth aperture (excludingaperture 250) which corresponds to states M M M and M signify anoversize board, while the apertures corresponding to states M M M and Mrepresent a normal board, and apertures corresponding to states M M Mand M represent undersize boards. The actual width is not significantsince only a one-out-of-three selection is to be made.

Clamps 144 and 160 are of the same construction as that shown in FIG. 7except that the shaft 186 and the entire photocell assembly are notpresent. Of course, cylinder wall 194 does not include the aperture 192therethrough, but the construction and operation is otherwise identical.

As shown in FIGS. 1, and 3 through 5, radial arm saw 28 is pivotallymounted on shelf 26 of saw table 12, whereby the saw blade 168 isangularly positionable within 290 from its normal position as in FIG. 5.Adjustment of the angular position of blade 168 is accomplished by meansof a step motor 268 which drives a worm gear 270 and wheel 272. Gearedwheel 272 is rigidly coupled to a rear column 274, which supports ahousing 276 at the upper end thereof. Within housing 276 is mounted anextensible arm 278 and with a reversible operating mechanism 280including an electric motor 282, a lead screw 284, and a threadedfollower 286 attached to arm 278.

Geared wheel 272 is rigidly attached to a vertical shaft 288 positionedwithin a dust-proof housing 290 resting on shelf 26 (see FIG. 3).Housing 290 includes an upper bearing 292 and a lower bearing 294 forrotatably supporting shaft 288.

An upper portion 296 of shaft 288 extends through an aperture 298 in thetop of housing 290 and is rigidly connected to an elongated tongue 300which extends forward from the base of column 274. Tongue 300 includesstepped shoulders 302 and 304 adapted to rest directly on the uppersurface 304 of housing 290, or

may include suitable rollers (not shown) to facilitate the movementthereof when wheel 272 is driven.

As shown in FIGS. 3 and 5,. vertical shaft 296 is located directly belowfence 158. Therefore column 274 travels over an extended arc as theblade angle is varied by step motor 268. While such a constructionrequires movement of a large mechanism, i.e., the entire saw 28, it hasthe advantage that irrespective of the angle at which the blade 168 isset, the saw crosses fence 158 at precisely the same point each time,simplifying the numerical control system and the operating program.

Motor 282, a reversable motor of any suitable type, drives lead screw284 which extends the full length of housing 276 within arm 278. Arm 278is a hollow rigid beam within which screw 284 travels. At the rear endthereof, is affixed the follower 286 which cooperates with lead screw284 to extend and retract arm 278 in accordance with the direction ofrotation of motor 282. As shown in FIGS. 3 and 4, one side of housing276 is open, thereby exposing arm 278 and facilitating the attachment ofa saw carrrige 306 thereto. The saw carriage 306 is of a conventionaltype such as is commonly used with radial arm saws, and includes a blademotor 307 and suitable means for attaching blade 168 thereto. Carriage306 is bolted or otherwise secured to arm 278 by means of a bracket 303.

Referring to FIG. 3, a pairof microswitches 310 and 312 are mounted atthe front and back ends respectively of housing 276 and are adapted tocooperate with an upwardly exending finger 314 attached to the back endof arm 278. Microswitches 310 and 312 are so positioned that when arm278 is extended its maximum forward distance, microswitch 310 isactuated to provide an electrical signal denoted as S which initiatesthe reversal of motor 282 in order to return arm 278 to its restposition. The rear microswitch 312 is actuated when arm 278 is in itsrest position, fully retracted, to provide a signal denoted as S whichserves, as explained below, to turn off both arm motor 282 and saw blademotor 307 after a cut has been completed.

The numerical control system for operating the above described apparatusis housed in console 18 which provides a suitable dust-proof enclosuretherefor. Console 18 carries a tape transport 316 for reading a punchedpaper or plastic tape 318 by which the numerical information for controlof the cutting process is supplied to the machine. Console 18 furtherincludes a material instruction display panel 320, and an operationinstruction display panel 322 by which the sawyer is provided all theinformation necessary to permit him to cut the entire truss. Displaypanel 320 includes an array of indicators 324, each of'which comprise atranslucent panel 326 having inscribed thereon the particularinformation to be conveyed. For example, a first series of 16 indicatorsare provided under the heading LENGTI-IS by which the operator may beinstructed to select a piece of stock lumber of sufficient length forthe particular segment of the truss to be cut. A second group of fourindicators under the heading SIZE is provided to identify thecross-sectional dimensions of the lumber, e.g., 2X3, 2X4, etc. Insimilar fashion, there are provided groups of indicators under theheadings QUALITY and SPECIES" to further identify the particular pieceof lumber to be cut.

Operation instruction display panel 322 includes six similarlyilluminated and inscribed indicator panels 328 to provide the sawyerwith step by step instructions as to the cutting of each segment in agiven truss. For example, in the particular embodiment shown herein, thesix indicators 132 may represent the following instructions: NEXT BOARD,DOUBLE CUT, OTHER END OF BOARD, END OF TRUSS, ERROR ON TAPE, and READY.As will be explained below, the instructions DOUBLE CUT and OTHER END OFBOARD are not really necessary, but simply serve to apprise the operatorof the nature of the next step to be carried out. Similarly, the ERRORON TAPE instruction serves only to warn the operator that improperinformation has been received, so that futher lumber will not be cut andperhaps wasted without first ascertaining and correcting the source oferror.

As may be understood, the NEXT BOARD and END OF TRUSS instructionsindicate to the operator that new lumber is to be obtained and/or thatthe previously cut material is to be collected and identified asbelonging to one particular truss. The READY instruction is providedwhen manual steps in the cutting operation are to be taken. As notedabove, convenience and flexibility dictate that the system does notoperate in a completely automated manner; therefore, at certain pointsin the operational program, control is temporarily turned over to thesawyer for certain steps. Following the completion of such steps, thesystem returns to automatic operation.

Electronics console 18 further includes a series of manual registrationunits 330 by which numerical information can be directly inserted intothe system for semi-manual setting of the dimension and angle at which aparticular cut is to be made. As explained below, the operator merelysets registration units 330 to the desired angle and dimensions. He thendepresses the appropriate one of control switches 34, and the registeredinformation is automatically recorded and the system is conditioned forcompletely manual operation.

Such operation would be desirable, for example, if a large number ofidentical segments are to be cut, or if the apparatus is to be used forsome purpose other than the manufacture of trusses as described herein.As may be understood, the automatic setting of the dimensions and anglesin respo nse to the insertion of numerical information by means of units134, is considerably more accurate and rapid than the manual setting ofthe saw and the measuring stops and in addition provides considerableflexibility in the use of the apparatus.

In addition, electronics console 18 may include suitable on-off switchessuch as 332 and 334 by which various portions of the system may beinitially placed in operation.

Referring now to FIG. 10, there is shown a generalized block diagram ofthe above described numerical control system. Shown are display panels320 and 322, a board width selection unit 336, including the board widthsensor 156 shown in FIG. 7, tape transport and reader 316 and a tapestepping logic unit 338. The system also includes an instructiontranslator 340, dimension and angle memory 342, manual angle and dimen'sion registration unit 330, angle indexer 344, which controls saw stepmotor 268, a coarse length indexer 346 which controls measuring stops106 and 132 and a fine length indexer 348 for controlling carriage stepmotor 150, an operation sequencer circuit 350 which provides over-allprogram control for the entire system, and an indexing and cuttingoperation programmer 351 which directs the setting of the angles anddimensions, and the operation of the saw 28.

The information to be displayed on panels 320 and 322 is provided over apair of signal paths, generally denoted as 352 and 354 from instructiontranslator 340 while operational control is provided over a further pairof signal paths 356 and 358 from operation sequence 350. Numericalinformation is supplied from tape reader 316 over a signal path 360 toinstruction translator 340 and thence over a parallel signal path 362 todimension and angle memory 342, described in detail below. Manualregistration units 330 are directly connected to memory 342 by signalpath 364.

Tape reader 316 is of any suitable well known type, and operates underthe control of tape stepping logic circuitry 338 to insert numericalinformation and commands into the system.

Instruction translator 340 receives the numerical information from tapereader 316 and converts it into an appropriate form for use by theremainder of the system. As previously indicated, instruction translator340 provides outputs over a series of leads 352 and 354 to displaypanels 320 and 322 and over a series of leads 362 to dimension and anglememory 9. In addition, to the previously mentioned outputs on signalpaths 352, 354 and 362, various operational commands are provided oversignal path 366 to operation sequencer 350.

Operation sequencer 350 operates as described below to conditionportions of the system at appropriate times in the operation cycle toestablish the order of the various steps which take place during thecutting of all of the lengths and angles of the segments of a truss.Operation sequencer 350 controls display panels 320 and 322 over signalpaths 356 and 358 as previously mentioned; and is also connected oversignal paths 368, 370, 372, and 374 to tape stepping logic 338, boardwidth selection unit 336, indexing and cutting operation programmer 351and dimension and angle memory 342, respectively.

Since the nature of the cutting operations are such that a certainamount of manual control is desirable, sequencer 350 is arranged so thatduring the operational cycle, automatic control of the system is halted,and external manual control transferred to the machine operator. Returnto automatic operation is accomplished by the depression of one ofmanual switches 34, which steps the tape reader to the next row ofinformation, and re-establishes automatic control. The manual tape stepcommand (which also serves to start the operation of the system) isprovided over lead 376 to tape stepping logic 338 from the switch 34.Operation sequencer 350 and tape stepping logic 338 serve as a closedloop clock when the system is operating automatically; therefore, theoutput of tape stepping logic 338 is returned to operation sequencer 350over lead 378 to indicate that the tape has been advanced and read, andto prepare sequencer 350 for the next command.

Board width selection generator 336 is connected to memory 342 by asignal path 380 and operates under control of sequencer 350 to selectthe appropriate angle and dimensions fortthe width of the board beingcut.

Memory 342 includes three registers for angle information, and 9registers for dimension information. According to the particularembodiment shown, a single word (including a plus or minus sign)characterizes each angle at which the lumber is to be cut; however, inorder to provide sufficient dimension accuracy, a separate numbercharacterizing the length in feet, the length in inches, and the lengthin 1/32 inches is necessary. Since three separate numbers are providedfor each dimension and angle, there is required three numbers (and threecorresponding registers) for each angle and nine numbers (and ninecorresponding registers) for each dimension. The numbers provided oversignal path 362 are stored in appropriate registers within memory 342under control of operation sequencer 350 over lead 374. In response toboard width selection signals over signal path 380, appropriate commandsare provided to angle indexer 344, to coarse length indexer 346 and tofine length indexer 348 for repositioning the associated measuring stopsand stop motors.

The operation of indexers 344, 346 and 348 is con trolled over signalpaths 382, 384, and 386, respectively by indexing and cutting operationprogrammer 351. Programmer 351 operates under the control of sequencer350 and by external signals from switches 34 to extend clamps 144, 146and 160 to start the saw blade motor 307, to advance and retract arm278, and to initiate the setting of the indexers. The various functionscontrolled by programmer 351 are so interconnected as to prevent theinitiation of a subsequent operation before completion of required prioroperations, both to promote operation safety and to assure accu rate,rapid and economical completion of the truss. Thus, information isreturned to programmer 351 over signal paths 388 and 390 from indexers344 and 348, respectively, and over signal path 392, from variousmachine sensors, described in detail below. Actuation signals areprovided over signal path 394 to the various clamp operating solenoids,to saw motor 307, and to the saw arm motor 282.

As previously mentioned, there are three basic configurations existingin which a given truss segment may be cut; in general, each truss maycomprise one or more segments of each configuration. In order to providecomplete automation and flexibility, the numerical control system of thepresent invention is adapted to automatically, and convenientlyaccommodate truss segments of all three configurations in any order andwithout the necessity of removing the piece of lumber from the machineuntil it is completely cut.

Thus, according to this invention, once the particular piece of lumberhas been identified by means of mate rial instruction display panel 320,the piece of lumber is chosen and placed on conveyor 14 and positionedagainst the first lumber stop 132 (see FIGS. 4 through 6) which stop isautomatically extended during the time that information as to therequired angles and lengths is being read into the system. In this way,stop 132 provides an initial reference mark L relative to which allfuture cuts in the truss segments are made. The system is so arrangedthat all subsequent cuts are made by simply moving the board to theright along measuring table 16, and abutting it against each of thestops 132 or 106 as they extend in sequence during each cut. In otherwords, at no time is it necessary for the piece of lumber to be moved tothe left in order to make a subsequent cut, nor will there ever arisethe situation in which a stop, having once been covered by the rightwardmovement of the piece of lumber, will be extended against the weight ofthe piece of lumber, thereby causing damage to it and possibly to'thelumber as well.

These statements may be more clearly understood by reference to FIGS.11a through 11,. which show the three basic configurations of the trusssegments. In FIG. 11,,, is shown what may be denoted as the SIN-GLE-SINGLE segment which is characterized by a single cut at each end atangles a and a separated by a distance L; The piece of lumber shown inFIG. 11,, is placed on the saw table 12 as shown in FIG. 11,,, ie theupper edge 396 thereof rests against guide fence 158. The points A and Brepresent those points at which saw blade 168 enters the piece of lumberthrough fence 158, and the angle a and a represent the complements ofthe angles to which the saw blade must be adjusted by step motor 268.

Shown in outline in FIG. 11, is a waste portion 398, which remains afterthe initial cut is made at angle a The end of the board 400 is locatedat point L which point is determined by the initial position of stop132. The second cut is made at point B, a distance L from the initialcut at point A; therefore the information provided on tape 318 is suchthat the second lumber stop position is a distance L from the initialposition at L If the truss segment is of the SINGLE-SINGLE type as shownin FIG. 11 the numerical information provided on the tape is as follows:

1. A first series of three numbers representing the alternative values(for oversized, normal or undersized lumber) representing the angle -a2. A series of nine numbers representing the distance L in (a) feet(three numbers) (b) inches (three num bers), (c) 1/32 inch (threenumbers);

3. Three numbers representing the angle 90-a Referring to FIG. 11,,there is shown what may be denoted as the DOUBLE-SINGLE truss segment,which includes a first cut at angle a and a second cut at angle a at thesame end of the board. The saw enters the board at point A for angle aiand at point B for the angle a points A and B being separated by thedistance L By comparison of FIGS. 11,, and 11 it may be seen that theonly difference between a single cut at both ends (FIG. 11 and a pair ofcuts at one end (FIG. 11,,) is that angle a in the SINGLE-SINGLE segment is less than 90 while the angle a in DOUBLE- SINGLE segment isgreater than 90. Therefore, no identifying information is in realitynecessary, other than the distance L and the value of angles a and a Forthe DOUBLE-SINGLE segment shown in FIG. 11,,, a third cut at angle a ismade at the far end of the board. For this cut, the saw enters thelumber at the point labeled C, a distance L from the point B. Thus,following the insertion of information regarding angles a L and a aseries of nine numbers representing the components of L and a series ofthree numbers representing the alternative values of a are provided onthe tape which are read, and utilized by the system as described below.In order to distinguish between the SIN- GLE-SINGLE segment and theDOUBLE-SINGLE segment, in the former case, instead of informationregarding length L and angle a there is provided a NEXT BOARD" or END OFTRUSS which resets the system.

In similar fashion, FIG. 11 shows the nature of the DOUBLE-DOUBLEsegment in which two cuts are present at each end of the board. Again,the first three cuts are made at points A, B, and C, and an additionalfourth cut making an angle a., is made at point D. As in the case of theDOUBLE-SINGLE segment points A and B are separated by the distance L,and points B and C are separated by the distance L In addition, points Cand D are separated by the distance L,,. Thus, in order to make theDOUBLE-DOUBLE segment, in addition to the information regarding anglesa,, a and a and lengths L and L,,, a further series of nine numbersrepresenting the components of L and a series of three numbersrepresenting the alternative values of the angle a, are provided on tape318 instead of the NEXT BOARD or END OF TRUSS words which would followthe a numbers in the case of the DOUBLE-SINGLE segment. Thus, the entireprocess is auotmatically controlled simply by the number and identity ofthe words appearing in succession on the tape, and no external settingof the machine to accommodate such variety of segments is necessary.

It should be noted, that in reality there are fourth and fifth types oftruss segments which are derivitives of those segments shown in FIGS.11a through 11c. These types of segments are characterized by either asingle or double cut at one end and by no cut or a right at angle at theother end. Such segments may of course be accommodated in thepresent-system, with no difficulty by recording on tape 318, sufficientinformation for the particular angles and lengths needed, followedeither by the NEXT BOARD or END OF TRUSS words.

In FIGS. 12 through 16, is shown a detailed block diagram of thenumerical control system of FIG. 10. FIG. 12 shows the details ofdisplay panels 320 and 322 tape reader 316, instruction translator 340,operation sequencer 350, tape stepping logic unit 338, and manualregistration unit 330.

Display panel 320 includes a plurality of illuminated two-terminalindicators 410,, through 410,,,, 412,, through 412,, 414,, through 414,,and 416,, through 416,, representing the initial lumber length, thecross sectional dimensions, the quality and the type of wood,respectively. All of the indicators are connected in common at oneterminal through a diode 417 to the ZERO level output of a first flipflop 418, which is selectively operable to condition or extinguishsimultaneously all of the indicators. The second terminal of each of theindicators is connected to a respective one of flip flops 420,, through420,,,, 422,, through 422 424,, through 422 and 424,, through 424,, inorder to provide selective illumination thereof. The reset input of allof the above denoted flip flops are connected in common over a lead 426to instruction translater 340 which provides a signal thereon wheneverthe NEXT BOARD word is read on the tape. In response to such a signal,all of the flip flops are reset, extinguishing all of the indicators inpanel 320.

The SET input for flip flop 418 is provided over lead 428 when operationsequencer 350 is in the A state as leads comprising signal path 352 frominstruction.

translator 340. In the present machine embodiment,

there is made provision for 16 possible lengths of the starting lumber,four different lumber cross sections, four different lumber qualities,and three different starting materials. However, only 16 connections arerequired between translator 340 and the coincidence gates associatedwith material instruction display panel 320, since the leads may be usedin common by all of the gates due to a time sharing thereof undercontrol of sequencer 350.

In particular, the words identifying the length, cross section, etc. ofthe required number appear in sequence on the tape. Therefore, thecorresponding coincidence gates may be conditioned in turn during the Athrough A states of sequencer 340 to register each word-on theappropriate indicators. The same word, e. g. T may represent the word 2FT. or 2X2 depending upon whether it occurs during the A or A state ofsequencer 350. I

Thus, in response to successions of signals in signal path 352, coupledwith appropriate conditioning signals on leads 438, 440, 442 and 444,one of the flip flops in each of the groups 402,, through 420,,,, 422,,through 422,, 424,, through 424,, and 426,, through 426,, will be set.However, in order not to confuse the operator, none of the indicators412, etc. are illuminated until all the information is received due toflip flop 418 being initially reset. After all the information isreceived, sequencer 350 enters the A state and flip flop 418 is set,thus providing a conduction path for the indicators appropriatelyconditioned by the previously set flip flops.

Display panel 322 comprises a series of illuminated indicators 446, eachbearing the appropriate designation to provide the sawyer with theoperational commands previously outlined.

One terminal of each of indicators 446 is connected in common to groundpotential over lead 448, while the second terminal is selectivelyoperated in response to signals from translator 340.

Each of indicators 446 except the READY indicator is connected to one ofa series of flip flops 450-458, the setting inputs of which areconnected to instruction translator 340. Flip flops 450-456 are set whenwords NEXT BOARD, DOUBLE CUT, OTHER END, and END OF TRUSS, respectivelyare present on the tape. Flip flops 450-454 is reset by means of asignal appearing over lead 460 from a manually operated switch 462 whichis depressed by the sawyer in order to lock clamps 154, 156 and 161.Flip flops 456 and 458 are reset by the NEXT BOARD word, and the END OFTRUSS words, respectively. The READY indicator requires no flip flop,but is connected by means of an OR gate 462 to program sequencer 350.The READY indicator is illuminated by a signal from OR gate 462 onlywhen automatic control is to be halted, and operation turned over to thesawyer. This occurs during the A A A and A states, as explained below.

Tape reader 316 provides a series of electrical signals on leads 464,,through 464,, representative of the code word present on the tape. Toconveniently accommodate all of the input information required foroperation of the system, e.g., the material identification words fordisplay panel 320, the operational commands for display panel 322 andthe angles and dimensions at which the lumber is to be cut, a suitablecoding scheme has been devised. In the embodiment shown, tape reader 316may be adapted to accommodate a standard eight hole tape; thus, an eightbit code is employed. Accordingly, there are 2 256 different code Wordsavailable.

As previously described, saw blade 168 is positionable at 1 incrementsslightly less than plus or minus 90 from the reference position taken tobe exactly perpendicular to guide fence 158. Thus, in addition to thesixteen material instruction words and the four operation instructionwords, there must be provided 180 angle instruction words to uniquelyidentify the angular position at which the saw is to be set. As in thecase of the material instructions, the 180 angle instruction words maybe time shared to provide the dimension instructions by conditioning theappropriate storage registers in synchronism with the arrival of thecorresponding instruction words.

Instruction translator 340 serves to convert the incoming informationprovided over leads 464,, through 464 from tape reader 316 into anappropriate form for use by the remainder of the system. Translator 340comprises a suitable coding matrix 466 and an error detection logiccircuit 468. Matrix 466 may be a semiconductor, or ferrimagnetic, etc.matrix of any known configuration and serves to convert each of theeight bit code words corresponding to the material instruction wordsinto a single output in one of terminals T through T and to convert theNEXT BOARD, DOU- BLE-CUT, OTHER END OF BOARD, and END OF TRUSS wordsinto a signal at one of outputs T through T respectively. The angle anddimension instruction words may be directly processed by the remainderof the system in the form of the eight bit code; therefore translatormatrix 466 provides a direct connection from tape reader 316 to angleand dimension memory 342.

Error detection logic circuit 468 analyses the incoming code words todetermine whether an error is present on the tape. In its simplest form,error detector 468 may simply comprise an OR gate connected to outputsof matrix 466 representing those of the 256 possible code words whichare not used for information. A more sophisticated error detector wouldbe arranged to analyze each incoming word and to reject even properwords if received at unexpected, or improper times in the operationalsequence. In addition, if 2 or less unique information words arerequired (or if a tape system having greater than eight holes per wordis used) than one or more parity bits may be used in order to provide anindication of the presence or absence of error on the tape. An outputfrom error detector 468 sets flip flop 548 to provide an alarm ifincorrect information is being received.

Operation sequencer 350 and tape stepping logic 338 cooperate to form aclosed loop pulsing system by which automatic control of tape reader 316is effected. Sequencer 350 comprises a 47 state ring counter 470, eachof which states is successively activated one at a time, by signals atan advancing input 472. Ring counter 470 includes second and thirdinputs 474 and 476 by which it may selectively be set into twoparticular states, namely the A and A states.

When manual insert switch 478 is depressed a signal denoted as S isgenerated and counter 470 is placed in the A state to permit angle anddimension information from registration unit 330 to be entered intomemory 342. Similarly in response to the receipt of a NEXT BOARD word byinstruction translator 340, the counter is set into the last state, i.e.state A Advance signals are provided in terminal 472 from a coincidencegate 474, which receives a first input over lead 476 from tape steppinglogic 338 and a second input over lead 478 from a flip flop 480. Flipflop 480 is set when the T NEXT BOARD word is received by instructiontranslator 340 to provide a conditioning signal for coincidence gate474. When gate 474 is so conditioned, and a pulse signal appears on lead476, counter 470 is advanced one state. Flip flop 480 is reset by the Tor END OF TRUSS word is received by instruction translator matrix 466 toprevent further advancement of counter 47 0 until a NEXT BOARD word isagain present on the tape.

As previously mentioned, various portions of the cycle generated bysequencing ring 470 call for successive automatic steps without anyaction by the sawyer. Among the automatic operations of this type arethe successive storage steps by which each of the three angleinstructions and nine dimension instructions are stored in memory 342.In each of these steps, successive operations of tape reader 316 areaccomplished by appropriate connection of the outputs of sequencing ring470 to tape stepping logic 338. Tape stepping logic 338 comprises amultiple input OR gate 482, a delay circuit 484, and a differentiationcircuit 486, a second OR gate 488 and a delay unit 490.

The outputs of sequencing ring 470 representing states A through A Athrough A A through A and A through A are connected as inputs to OR gate486. Thus, when ring counter 470 is in any of these states, a delayedsignal is transmitted to the input of differentiator 486, which respondsto the leading edge thereof, and provide a pulse input to OR gate 488.The output of OR gate 480 is provided to an advance input 492 of tapereader 316 which steps the tape forward and causes the next word on thetape to be read.

OR gate 488 receives as a second input a signal de' noted as S, fromtape stepping switch 494 in order to return the system to automaticoperation following the required manual steps, or to initiate theoperation of the system at the time a new tape is inserted into tapereader 316. The advance input for operation sequencer 350 is provided byOR gate 488 through a delay circuit 490, which delay is of appropriateduration to maintain accurate synchronization between the various stepsin the program.

Manual angle and dimension registration unit 330 comprises a pluralityof decade potentiometers or continuous potentiometers coupled withsuitable quantizing circuitry. These circuits serve to permit the directinsertion into the system of particular angles and dimensions at which apiece of lumber is to be cut. The desired numbers are set in circuit 330and manual insertion switch 478 is depressed. This causes the signal Sto set sequencing ring 470 in the A state as previously mentioned, andin addition, it establishes indexing and cutting operation programmer351 in the condition required for non-automatic operation with themanually inserted angle and dimension data as described below.

In FIG. 13 are shown the details of indexing and cutting operationprogrammer 351. A first coincidence gate 496 is connected to the outputof OR gate 460 and switch 478. The output of gate 496, denoted as I isconnected to the solenoids of valves 178 and 182 as described inconnection with FIG. 7. Thus, if ring 470 is in any of the A A A or Astates, and the operator depresses switch 462 the cutting operation isinitiated. If ring 470 is not in the above states, the system is inautomatic operation and the sawyer cannot interrupt the sequence.

Assuming the system is conditioned for manual operation, the claimsclose, and microswitches 206 are actuated, coincidence gate 214 (FIG. 7)is activated and provides a signal denoted in I to condition a secondcoincidence 498. A second input to gate 498 denoted as S is providedwhen out switch 500 is depressed by the operator. Upon coincidence ofsignals S and 1 a signal I is generated by gate 498 to initiate theoperation of angle indexer 344. I is also connected to a delay circuit502, an OR gate 504, and a further delay circuit 506 which in turn isconnected as a first input to a coincidence circuit 508. The I signalalso serves as a safety switch to turn off all motors when either switch462 or 500 is released.

The output of delay circuit 502, denoted as I is connected as the setinput of a flip flop 510 and as a start signal for fine length indexer348. The ONE output of flip flop 510, denoted as 1 serves as explainedbelow to initiate the operation of coarse length indexer to extend onesof stops 106 or 132, while the complement signal 1 initiates theretraction of the stops.

The reset input for flip flop 127 is provided by a differentiator 515and an OR gate 504 which receives as its second input, the T or NEXTBOARD output of instruction translator matrix 466.

As previously indicated, a first input to coincidence gate 508 isprovided through a delay circuit 506 by the output of coincidencecircuit 498. The second and third inputs to coincidence gate 508 areprovided over leads 388 and 39 from angle indexer 344 and fine lengthindexer 348, respectively, only when the indexers are balanced, i.e.when the respective step motors are not in motion. The presence of thethree inputs to coincidence gate 508 serves as an electronic interlockto prevent the operation of blade motor 307 and arm motor 282, when theindexers are changing either the blade angle or the position of one ofthe retractable stops.

The output of gate 508 is connected through a differentiation circuit512 as the set input to a flip flop 514, which in turn provides a signalI to operate blade motor 307. The reset input to flip flop 514 isprovided by means of a further differentiator 516 from the output S ofrear microswitch 312 (see FIG. 3) whereby the complete retraction of arm278 causes the blade motor 307 to be shut off.

The output of coincidence circuit 508 and differentiator 512 is providedthrough a further delay circuit 518 as a set input for an additionalflip flop 520, which generates ONE output 1 to operate arm motor 202 inthe forward direction. The reset input of flip flop 520 is provided froman OR gate 522. The S and S signals are fed through a pair of inverters524 and 526 as first and second inputs to gate 522, which inputs arepresent when switches 462 and 500 are released. A third signal S isprovided when forward microswitch 310 is actuated by the passagethereover of finger 312 of arm 278. OR gate 522 therefore provides anadditional safety interlock whereby the release of either clamp switch462 or cutting switch 500, or the extension of arm 278 to its maximumposition causes the resetting of flip flop 520 and the correspondingreversal of arm motor 282 thereby causing the return of saw carriage 306to its normally conditioned inhibit gate 528 connected to the ZEROoutput of flip flop 520. The inhibit signal S for gate 528 is providedfrom rear microswitch 312 so that when the saw has completely returnedto its rest position, arm motor 282 is stopped.

Indexing and cutting operation programmer 351 includes a further Or gate530 which generates a signal I for dimension and angle memory 342. Theinputs for gate 530 are the T and S NEXT BOARD and MAN- UAL INSERTsignals, and signals representing the A A and A states of ring counter470. As explained below the 1 signal clears the registers in memory 342in preparation for the storage of new information.

In FIG. 14 are shown the details of board width selection generator 336.The circuitry includes ring counter 242 and inverter 248, previouslymentioned, three OR gates 532, 534 and 536, three correspondingcoincidence gates 538, 540, and 542, and three flip flops 544, 546 and548.

Each of the ring counter outputs which corresponds to an oversizedboard, i.e. M M M and M are connected to OR gate 352, while each of theoutputs corresponding to normal size and to undersized boards areconnected to OR gates 534 and 536, respectively. Thus, a signal at theoutput of one of OR gates 532, 534 and 536 is indicative that the boardis oversized, normal or undersized, respectively, irrespective of itsactual width.

Board width measurement takes place when the board is first inserted inthe apparatus, i.e. immediately prior to the first cut. To this end, theoutput of OR gates 532, 534, and 536 are connected to coincidence gates538, 590 and 542, respectively. Second inputs to the coincidence gatesare provided from the A output of program sequencing ring 370. Also,while clamp 156 is closing, no meaningful indication can be obtainedfrom ring counter 242. Therefore, the I, signal is also connected as aninput to gates 538 through 542. Until the I signal is present,indicating complete closure of clamp 156, no output is provided from anyof the coincidence gates 538 through 542.

As may be understood, depending upon the width of the board, one of thecoincidence gates will be activated, thereby providing a set input toone of flip flops 544 through 548. The flip flop remains set until areset signal, is provided in common to the preset input of all of theflip flops 544 through 548 from the T output of instruction translatormatrix 466.

The output of coincidence gate 538 is connected to the set input of flipflop 544 through an OR gate 550. The second input to OR gate 550 isprovided over from manual insertion switch 478, in order to arbitrarillyactivate flip flop 544, whenever manually inserted data is to be used tocut the lumber.

Board width selection generator 336 further includes two tri ads ofcoincidence gates 552-554-556, and 558-560-562. Coincidence gates 552and 558 each receive a first input from the output of flip flop 544,while coincidence gates 554 and 560 and 556 and 562, each receive afirst input in common from the output of flip flops 549 and 548,respectively. The second input to coincidence gates 552-554-556 isprovided in common by the 1 (start fine length indexer) signal, fromindexing and cutting operation programmer 351, while the second input tocoincidence gates 558-560-562 is provided in common by the I (startangle indexer) signal. The outputs of coincidence gates 552-558-556denoted as 1 -1 and the outputs of coincidence gates 558-560-562,denoted as l -I serve to select the appropriate length angle settings inaccordance with which of the flip flops 544-548 has been set by boardwidth sensor 156.

In FIGS. and 16 are shown the details of dimension and angle storagememory 342. As noted, three separated registers are required for theangle command, while nine separate registers are required for thedimension instruction. Accordingly, memory 342 includes angle registers564, 566, and 568, three L (feet) registers 570, 572, and 574, three L(inch) registers 576, 578, and 580, and three L (1/32) registers 582,584, and 586. Each of registers 564 through 586 comprises a number ofmemory elements to accommodate the eight bit code by which theinstructions are represented and are all connected in common to leads464,, through 464,, of instruction translator matrix 466. Each of theregisters further includes internal circuitry to selectively permit theinsertion of data into the register, when a signal is present at aso-called SET input and to prevent the insertion of data at all othertimes. The SET input to each of registers 564 through 586 are providedby a respective one of OR gates 588 through 610. The inputs to OR gates588 through 610 are provided by appropriate ones of the outputs ofprogram sequencing ring 470, whereby information stored in the variousregisters can be changed only during predetermined portions of thesystem operation cycle.

Each of registers 564 through 586 further includes CLEAR input labeledto selectively erase the information stored therein prior to theinsertion of new information. The erase signal for registers 564 through586 is provided by the I, from indexing and cutting operation programmer351, however during the A state, no erasure of registers 570-586 isnecessary. Thus, the erase signal for the latter nine registers isdelivered provided in common over lead 151, from indexing and cuttingoperation programmer 351 by an inhibit circuit 512 which isblocked'during the A state. Thus, at appropriate times in the operationcycle, the registers will be cleared, and subsequently, information willbe in serted, all under control of operation sequencer 350.

Each output of registers 564 through 586 is connected to individualmembers of sets 616 through 638 of coincidence gates which serve toselectively switch ones of registers to the indexers 344-348. Theenabling inputs for each of sets of gate 616 through 620 is provided byone of signals l -l while sets of gates 622-638 are enabled by one ofsignals 1 -1 from indexing and cutting operation programmer 351. Inparticular, registers 564, 570, 576 and 582 are adapted to storeinformation for the cutting of oversized boards, registers 566, 572,578, and 584 are adapted to store information corresponding to normalsize boards and registers 568, 574, 580 and 586 adapted to storeinformation corresponding to undersized boards. Accord ingly, gate sets616, 618 and 620 are conditioned by the I ,-I signals, respectively. Insimilar fashion, gate sets 622, 628 and 634,are operated in common byoversize length selection signal 1, gate groups 624, 630 and 636 areoperated by normal length selection signal 1 and gate sets 218, 221 and224 are operated by undersized length selection signal 1 Once theparticular angle and dimension has been selected, the remainder of thesystem does not require any knowledge as to which selection was made.Accordingly, corresponding outputs from angle selection gate sets 616-620 are connected in common to one of a series of OR gates 640, whichprovide numerical information to angle indexer 344. Similarly,corresponding outputed of L( feet) selection gates sets 622-626 areconnected in common through a second series of OR gates 642 as thenumerical inputs to coarse length indexer 364, while the outputs of L(inch) selection gates 628 through 632 and L (1/32) selection gates 634through 638 are connected in common to sets of OR gates 644 and 646,respectively as to inputs of fine length indexer 348.

Coarse length indexer 346 comprises a translator matrix 648, and aseries of coincidence gates 650 which provide setting inputs to acorresponding series of flip flops 652. The reset inputs for flip flops652 are provided by the I signal, as previously described. The outputsof each of flip flops 652 are connected respectively to the actuator ofone of stop mechanisms 106 and 132 shown in FIG. 1, to extend the stopin accordance with a signal passed from translator matrix 648 whenevercoincidence gates 650 are conditioned by the 1 signal from programmer351. The first of flip flops 652 is set by an OR gate 654 which receivesboth a signal from the first of gates 650, and also the A signal. Inthis manner, the distance L, referred to in connection with FIGS.Ila-11c is set at the beginning of each board.

With regard to fine length indexer 346 a single setting of carriage 58is effected in accordance with the information provided by one of theL(inch) and L(1/32) registers. Indexer 346 includes a translator matrix656, and a step motor control circuit 658 described in detail below.Matrix 656 is arranged to respond to a digital code provided from setsof OR gates 644 and 646 to provide a further digital code word whichrepresents, as explained below, the number of independent steps requiredby the length step motor (see FIG. 5) which would be required to achievethe proper positioning of the extended stop if the indexer were set atits zero position.

Translator matrix 656 also receives the A state input which causes it togenerate the inch and 1/32 inch setting for the distance L whereby thereference distance for carriage 58 is established.

The output of translator matrix 656 is the numerican input to step motorcircuit 658, the numerical input to angle indexer 344 is directlyprovided to a step motor control circuit of the same type as step motorcircuit 658 in length indexer 348 without the use of a separatetranslator since only a single number, i.e. the angle in degrees isemployed.

The details of step motor control circuit 658 are shown in FIG. 17. Thecircuit includes a series of coincidence gates 660, which receive theinput signals, e.g., from translator matrix 656, an input register 662 adigital subtraction circuit 664, a direction and zero sensing circuit668, a pulse oscillator 670, a further coincidence gate 672, a referenceposition sensor 674 and a present position register 676. The step motor,denoted at 677 corresponds either to step motor 150 or 268 and mayinclude a mechanical actuator and an associated microswitch (not shown)which comprises reference position sensor 674.

1. A cutting machine comprising a framework including a cutting surfacecomprised of a table adapted for receiving a wooden member, cuttingmeans comprising a blade, first control means for providing a firstmotion to said blade to effect a cut on said wooden member, secondcontrol means for providing a second motion to said blade relative tosaid wooden member for engaging said blade with said wooden member;reference position means including a guide fence for supporting andaligning said workpiece in relation to said blade, a carriage mounted onsaid framework for movement therealong, a plurality of stops carried bysaid carriage and movable therewith along said cutting surface andparallel to said fence for establishing distances of cuts between saidblade and said stops, each of said stops being movable from a firstposition spaced from said cutting surface into a second positionproviding an abutment for an end of said wooden member, means for movingsaid stops from said first position to said second position, means forpositioning said carriage along said framework and thereby positioningsaid stops relative to said cutting surface to establish select cuttingdistances between said stops and said blade; means providing data in theform of electrical signals representing a predetermined distance betweena selected stop and said blade, means responsive to said signals forcontrolling said positioning means to locate said carriage in a positionwhereby said selected stop is located at a the predetermined distancefrom said blade, said signal responsive means including means foractuating the stop moving to move said selected stop from a first to asecond position, and means for clamping said wooden member to said tablesurface thereby holding said wooden member rigid during a cuttingoperation.
 2. A machine according to claim 1 including means foractuating said clamping means, said signal responsive means beingoperable to retract the selected stop from engagement with said woodenmember in response to actuation of said clamping means.
 3. A machineaccording to claim 1 including means for moving said wooden memberacross said table for engagement against said guide fence.
 4. A machineaccording to claim 1 wherein said clamping means applies a force to saidwooden member in a direction opposite to the second direction ofmovement of said blade.
 5. A machine according to claim 1 wherein saidfirst control means includes a motor for rotating said blade, andwherein said second control means includes means for translating saidblade while the same is being rotated to engage said blade with saidwooden member.
 6. A cutting machine as defined in claim 1 wherein saidsignal responsive means includes memory means for storing saidelectrical signals, said positioning means being operable in response tothe pattern of signals in said memory means.
 7. A cutting machine asdefined in claim 6 wherein said data is provided in blocks and whereinsaid memory means includes individual memory elements, means forconnecting each memory element in turn to said data source to store aparticular portion of each data block, and means coupling saidindividual memory elements to said positioning means.
 8. A cuttingmachine as defined in claim 6 wherein said positioning means includesmeans responsive to at least a portion of the signal pattern in saidmemory to control the position of said carriage relative to saidframework.
 9. A cutting machine as defined in claim 8 wherein said meansfor moving said carriage comprises a reversible motor operative inresponse to a portion of said signal pattern, a lead screw driven bysaid motor, and a follower attached to said movable carriage and adaptedto cooperate with said lead screw for moving said carriage toward oraway from the blade in accordance with the direction of rotation of thelead screw.
 10. A cutting means as defined in claim 5 wherein saidsecond control means comprises an arm for movably supporting said sawblade and blade motor, an arm motor, means driven by said arm motor toextend and retract said saw blade along said arm, and manual switchmeans to actuate said blade motor and said arm motor under control of anoperator.
 11. A cutting machine as defined in claim 1 wherein saidsignal responsive means comprises means for receiving signalscorresponding to said predetermined distance between said selected stopand said blade, means for receiving information regarding the actualdistance between said selected stop and said blade, means for comparingsaid actual distance and said predetermined distance and for providing adifference signal, means responsive to said difference signal to operatesaid positioning mechanism to reduce the difference between the actualand predetermined distances and to provide an indication when the actualdistance equals the predetermined distance.
 12. A cutting machine asdefined in claim 1 including further signal responsive means for storingdata representing identifying characteristics for selecting the woodenmember, and means for displaying said identifying data in visible form.13. A cutting machine comprising a framework including a cutting surfacecomprised of a table adapted for receiving a wooden member, cuttingmeans comprising a blade, first control means for providing a firstmotion to said blade to effect a cut on said wooden member, secondcontrol means for providing a second motion to said blade relative tosaid wooden member for engaging said blade with said wooden member;reference position means including a guide fence for supporting andaligning said workpiece in relation to said blade, a carriage mounted onsaid framework for movement therealong, a stop carried by said carriageand movable therewith along said cutting surface and parallel to saidfence for establishing a distance of cut between said blade and saidstop, said stop being adapted to provide an abutment for an end of saidwooden member, means for positioning said carriage along said frameworkand thereby positioning said stop relative to said cutting surface toestablish select cutting distances between said stop and said blade;means providing data in the form of electrical signals representing apredetermined distance between said stop and said blade, meansresponsive tO said signals for controlling said positioning means tolocate said carriage in a position whereby said stop is located at thepredetermined distance from said blade, and means for clamping saidwooden member to said table thereby holding said wooden member rigidduring a cutting operation.